{"id":"CVE-2026-46340","aliases":["GHSA-5xrh-qmmq-w6ch"],"url":"https://o3.security/vulnerability/CVE-2026-46340","summary":"Netty: SCTP reassembly nests buffers without bound","details":"Netty is a network application framework for development of protocol servers and clients. In versions of netty-transport-sctp prior to 4.1.135.Final and 4.2.15.Final, for each non-complete SctpMessage fragment the handler does `fragments.put(streamId, Unpooled.wrappedBuffer(frag, byteBuf))`, wrapping the previous accumulator and the new slice into a *new* CompositeByteBuf every time. After N fragments the accumulator is an N-deep chain of composites, each holding references and component arrays; readableBytes()/getBytes() on the final buffer recurse N levels. There is no limit on N, on total bytes, or on the number of streamIdentifiers an attacker can open (each gets its own map entry). A peer that never sets the `complete` flag can grow this structure indefinitely from tiny 1-byte DATA chunks. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","published":"2026-06-12T14:19:48.855Z","modified":"2026-08-12T03:51:47.348960384Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00449,"percentile":0.36876,"asOf":"2026-08-10"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-transport-sctp","fixedVersion":"4.2.15.Final"},{"ecosystem":"Maven","name":"io.netty:netty-transport-sctp","fixedVersion":"4.1.135.Final"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.1.135.Final"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.15.Final"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46340.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:37390"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:41951"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:50085"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-46340"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46340.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-5xrh-qmmq-w6ch"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46340"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2488388"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:47.348960384Z"}}